﻿/**
 * SlotDuino
 * 
 * Copyright (c) 2011/2012 Thiago Hummel Moreira, Ricardo Mizuuti, Rafael Mufato, Bruno Sakai, Andre Turina
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace SlotDuino.Sockets
{
    public class DatagramListener
    {
        #region Private attributes
        private int _port = 12345;
        private IPAddress _address = IPAddress.Any;
        private Socket _listenSocket;
        private Thread _thdListener;
        private bool _stopThreads = true;
        #endregion

        /// <summary>
        /// This event will provide the remote end point and the received data to handlers
        /// </summary>
        public event DatagramReceivedEventHandler DatagramReceived;

        #region Constructors
        public DatagramListener()
        {
        }

        public DatagramListener(int port)
            : this()
        {
            _port = port;
        }

        public DatagramListener(int port, IPAddress address)
            : this(port)
        {
            _address = address;
        }
        #endregion

        #region Public Properties
        public int Port
        {
            get { return _port; }
        }

        public IPAddress Address
        {
            get { return _address; }
        }
        #endregion

        #region Listener public control methods
        public bool Start()
        {
            try
            {
                if (_stopThreads)
                {
                    _stopThreads = false;

                    _listenSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                    _listenSocket.Bind(new IPEndPoint(_address, _port));

                    //Start the listener
                    _thdListener = new Thread(new ThreadStart(ListenerThread));
                    _thdListener.Start();
                }
            }
            catch (Exception)
            {
                Stop();
                return false;
            }

            return true;
        }

        public bool Stop()
        {
            if (!_stopThreads)
            {
                _stopThreads = true;
                return true;
            }

            return false;
        }
        #endregion

        private void ListenerThread()
        {
            EndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);

            while (!_stopThreads)
            {
                if (_listenSocket.Poll(500000, SelectMode.SelectRead))
                {
                    if (0 < _listenSocket.Available)
                    {
                        byte[] inBuf = new byte[_listenSocket.Available];
                        int bytesReceived = _listenSocket.ReceiveFrom(inBuf, ref remoteEP);
                        if (0 < bytesReceived)
                        {
                            OnDatagramReceived(inBuf, ref remoteEP);
                        }
                    }
                }
            }

            _listenSocket.Close();
#if DEBUG
            Console.WriteLine("UDP Listener dies...");
#endif
        }

        private void OnDatagramReceived(byte[] data, ref EndPoint remoteEP)
        {
            DatagramReceivedEventHandler handler = DatagramReceived;

            if (handler != null)
                handler(this, new DatagramReceivedEventArgs(data, ref remoteEP));
        }
    }

    #region Event support classes
    public class DatagramReceivedEventArgs : EventArgs
    {
        private IPEndPoint _remoteEP;
        private byte[] _data;

        #region Public Properties
        /// <summary>
        /// The received data
        /// </summary>
        public byte[] Data { get { return _data; } }

        /// <summary>
        /// The client endpoint
        /// </summary>
        public IPEndPoint RemoteHost
        {
            get { return _remoteEP; }
        }
        #endregion

        public DatagramReceivedEventArgs(byte[] data, ref EndPoint remoteEP)
        {
            _data = new byte[data.Length];
            Array.Copy(data, _data, data.Length);

            var remoteIP = (IPEndPoint)remoteEP;
            _remoteEP = new IPEndPoint(remoteIP.Address, remoteIP.Port);
        }
    }

    public delegate void DatagramReceivedEventHandler(object sender, DatagramReceivedEventArgs e);
    #endregion
}
